1. Field of the Invention
The present invention pertains generally to surgical instruments and, more particularly, to surgical instruments such as surgical tool drivers particularly suited for use in orthopaedic surgical procedures.
2. Description of the Related Art
An orthopaedic reamer assembly is used to cut a bone and thereby form the bone with a predetermined shape for receiving an orthopaedic implant. For example, an intramedullary reamer may be placed into the intramedullary canal of the bone and used to ream the interior of the bone to receive the stem of an orthopaedic implant. Such a reamer includes a radial, peripheral surface which generally includes a plurality of radially extending teeth for cutting the bone in a radial direction as the reamer proceeds in an axial direction into the bone. The size of the opening formed in the bone is determined by the outside diameter of the reamer.
An orthopaedic reamer assembly may also be used to shape an exterior surface of a bone. A rotary tool provides the motive force and is connected to a driver which is connected to the reamer. The driver generally has a shaft and a drive end. Reamers are typically hemispherical in shape and attach to the drive end at the base of the hemisphere. The distal face has a shape which corresponds to the shape of an orthopaedic implant to be received within the bone, and includes a plurality of cutting teeth extending from the distal face. The reamer is placed against the bone surface to be cut, such as an acetabulum or glenoid, and is plunge cut into the bone. Such reamers are effective for removing a portion of the bone so that the bone is shaped to receive the implant.
Minimally invasive surgery reduces the size of the incision site to in turn reduce trauma and recovery time for a patient. Orthopaedic reamers have been designed for minimally invasive surgery, e.g., U.S. patent application Ser. No. 10/659,812, assigned to the assignee of the present invention. A challenge with minimally invasive and certain other orthopaedic procedures is that it may be difficult to position the reamer at a desired angle relative to the bone surface to be cut. Orthopaedic reamer drivers are known which have a flexible shaft. The flexible shaft allows the reamer to travel along the path of a non-linear passage, such as an intramedullary canal, and thereby ream a non-linear opening. However, such a known driver having a flexible shaft cannot be held with the reamer positioned at a fixed acute angular orientation relative to the drive shaft since there is nothing to hold the reamer at that orientation during rotation.
What is needed in the art is an orthopaedic reamer driver which holds the reamer at a selected one of a plurality of angular orientations relative to the drive shaft while still allowing rotation of the reamer.